An MRAM has many individual cells, each cell comprising a magnetic tunnel junction. During a read operation, certain cells in the MRAM are selected. Other partially selected cells, which are generally the cells on the same bit lines as the selected cells, will have leakage current through them. The higher the leakage current, the harder the task becomes of correctly reading the stored information in the selected cells, causing slower access times. Additionally, high leakage current causes increased power consumption during reads, militating against a major benefit of MRAMs, which is low overall power consumption. Moreover, the relatively high leakage current reduces the attainable size of an MRAM.
There are several techniques available for minimizing leakage current through partially selected cells. However, these techniques have the detriments of increased manufacturing cost and time, larger cell structures, and increased cell complexity.
Consequently, a need exists for reducing leakage current through partially selected MRAM cells without introducing increased manufacturing costs, cell size and complexity.